Cereal mills are driven by powerful diesel engines that can smoke and overheat if not properly set-up. An incorrect adjustment, particularly for older, mechanically-governed engines, can result in smoking, not just during cranking, but also during normal operation. This not only looks bad, but also wastes fuel. Black smoke is simply unburned diesel, which costs money but produces no power.
Naturally, a free-flowing air inlet is just as important as a correctly functioning injection pump.
Another common problem with mobile cereal mills is overheating. A ‘healthy’ exhaust temperature would be around
The recommended Service items are:
Determine the correct settings and make the required adjustments.
Remove and measure on the Test Bench. If necessary, dismantle, service and re-build.
In sequence all Injectors to be removed and tested. Injectors to be dismantled and any worn parts replaced as required.
Due to the high temperature of operation the Turbocharger is invariably damaged in some way. During this service the Turbo is routinely swapped for a relatively inexpensive exchange unit.
If the Injection pump of the engine is fitted, as standard, with a mechanical governor, this can be upgraded. Mechanical governors have the disadvantage that they react relatively slowly. It requires a speed difference of at least 70 rpm, before they act. By the time a mechanical governor reacts to a fall in engine speed, it must provide extra fuel to return to the correct speed.
The electronic governing system from GAC is much more accurate than a mechanical governor.
550 °C. In practice it is not at all uncommon for the exhaust temperature to measure between 800 and 900 °C, so that the complete exhaust system glows red-hot under full load. No turbocharger can stand this for very long.
Furthermore continuous working at a fixed speed is healthier for the engine, in the long-run, than constant stopping and starting.
Against this background of commonly recurring problems the company August Storm GmbH & Co. KG (Engine Commissioning & Servicing) have put together a package of recommended service items.
An electronic governor on the other hand can drastically reduce speed oscillations. It is possible to remove a mechanical governor from the rear end of the injection pump and replace it with an electronic one. Storm fits electronic governors from GAC.
In order for the governor to measure the actual engine speed a pick-up sensor must be mounted into the engine bell-housing. It must be positioned accurately over the flywheel ring-gear in order to ‘count’ the teeth as they pass.
The pick-up passes its signal to an electronic box that processes it. The output signal from this box passes through another cable to the GAC actuator positioned on the fuel injection pump and controls the fuel supply. This electronic system functions much faster and is able to hold the desired speed more accurately.